Power transmission



3 Sheets-Sheet 1 E. L. ROSE POWER TRANSMISSION Filed April 28, 1941 INVENTOIIQ. EDWIN ROSE ATTORNEY Jan. 13, 1942.

Jan. 13, 1942. E. L. ROSE 2,269,786

POWER TRANSMISSION Filed April 28, 1941 I 5 Sheets-Sheet 2 INVENTOR EDWIN L. ROSE ATTORNEY Jane 139 E. L. POWER TRANSMISSION Filed April.28, 1941 v 3 Sheets-Sheet 3 I III INVENTOR' EDWiN y L. ROSE ATTORNEY Patented Jan. 13, 1942 UNITED STATES PATENT oFFlcE rowan TRANSMISSION Edwin L. Rose, Woodbury, Conn, assignor to Vickers Incorporated, Detroit, Mich, a corporation of Michigan Application April 28, 1941, Serial No. 390,686.

-11 Claims. This application is a continuation-in-part of,

"my copending application Serial No. 144,916, filed May 26, 1937, for Power transmission.

This invention relates to power transmissions and moreparticularly to a hydraulic power transmission system for operating an elevator.

It is an object of the present invention to procumulator may be utilized for operating the elevator at least through one cycle in an emergency, should the power driven pump be inoperable for any given reason.

to the'fluid m'otor l9 through a conduit is a hydraulic accumulator 22 having a piston 23 which is biased downwardly by a weight 24 carried on a platform 25. The second fluid motor, 2| is connected by a conduit 28 to one port 28 of a reversible variable displacement pump 80. The pump 80 may be of any suitable construction, such as the well-known Waterbury type. A prime mover, such as an electric motor 82, is connected to the drive shaft 34 of the pump 80.

The other port 38 of the pump is connected by a conduit 38 to a port 40 in a three-position control valve 42. A branch conduit 44 connects the accumulator to a port 46 in the valve 42. In the normal power operatingposition of the valve .42 which is illustrated in Figure 1, the movable element 48 of the valve and 45. i

The valve 42 is also provided with a port 50 which is connected. by a branch conduit 52 to 42 connects the ports 40 the fluid motor-2| through the conduit 28. A

' port 54 in the valve 42 is connected by a conduit The invention is disclosed as applied to an elevator such as one commonly used for transfer-' rin'g passengers or goods between floors of a building although it will be understood that in this specification and the claims hereto appended the term elevator is intended to comprise any device in which the force of gravity or any equivalent constantly acting force must be selectively either overcome or allowed to move the load device.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompany- .ing drawings wherein a preferred form of the presentinvention is clearly shown.

In the drawings: 7

Figure 1 is a diagrammatic view of a hydraulic elevator system incorporating a preferred form of the present invention.

56 with an overflow tank 58 which is also connected by a branch conduit with'the space at the lefthand end of the valve 42. An auxiliary'pump 82 driven by an electric mo tor 84 serves to withdraw fluid from the overflow'tank 58 and deliver the same through a conduit 66 to the port 48 and to the accumulator. 22 through the conduits 4'4 and 20. The motor'it'is'under the control of a float-actuated switch 68' so that the pump'62 operates to maintain the level in the tank 58 below a predetermined point.

The pump 30 is under the control of a followup control system, the details of which are illustrated in Figure 2. The displacement and the direction of discharge in pump 30 may be varied by the operation of a rotary control shaft 10.

,The latter has rigidly secured thereto a worm- Figure 2 is a view corresponding to Figure 1 showing the parts in a difierent position.

Figure 3 is a view corresponding to Figure 1 showing the parts in a third position.

Referring now to Figure l the elevator platform is represented at l0 and is operable in a well 12. Secured to the bottom of the platform l0 isa hollow ram l4 operable in a cylinder l6 having an upstanding plunger portion l8. The

forms-one fluid motor [9 while the space within space in the cylinder around the plunger l8 wheel 12 adapted to be driven by a worm'll secured to a shaft 16. The latter carries a planet carrier 18 to which are pivoted a pair of bevel planet pinions 80. meshing with bevel gears 82 and 84, coaxial with the shaft 16. The bevel gear 82 has secured thereto a pulley 86 over which is wound a cable 88 running over idler pulleys 90 and passing around a pulley 92 at the lower end of the elevator well l2. Rigidly secured to the pulley 92 is another pulley 84 carrying a cable 96 which also passes over a pulley 98 at the top of the elevator well. The two ends of the cable 96are secured to the elevator platform l0 as illustrated in the drawings.

The bevel gear 84 carries anotherbevel gear I00 which actuates the screw shaft I02 of a'limit provided with a spring-closed, solenoid-opened brake I08 which is connected in circuit with themotor to maintain the same locked whenever the motor is deenergized. Suitable Raise and Lower push button switches H and H2 are .provided in series with the limit switches to control actuation of the pilot motor I 04. in a forward or reverse direction.

In operation under normal conditions the valve 42 is held in the central position as illustrated in Figure 1. Under these conditions the ports 40 and 46 are incommunication, the ports 50 and 54 being isolated. Assuming the elevator to be at the bottom of the well, the Raise" push button I I0 may be closed causing the pilot motor I 04 to rotate, driving the worm 14 through the differential gearing 80, 82 and 84 and moving the rotary control shaft 10 into stroke in a direction to force fluid from the port 36 to th port 28. Fluid from the accumulator 22 is thus supplied not only to the first fluid motor l9 through the conduit20, but is also supplied to the second fluid motor 2i through conduits and 44, valve 42, conduit 38, pump and the conduit 20. The elevator is thus caused to rise, turning the pulleys 92 and 94 and through the cable 88 operating the drum 8B in the reverse direction to that in which the bevel gear 84 is turning.

As soon as the normal elevator speed, which is a speed corresponding to that of the pilot motor I04, is reached the worm 14 will stop rotating leaving the pump in whatever stroke it happened to be when the elevator speed caught up with the pilot motor speed. Before the end of the elevator stroke is reached, the limit switch .in series with the push button I I0 is opened stopping the motor I04. Thereupon continued movement of the elevator rotates the worm 14 in the opposite direction, returning the pump shaft I0 In order to conserve power, that is, to store the potential energy of the empty elevator at the top of its stroke, the area of the flrst fluid motor I! is made such that at the pressure normally maintained in the accumulator 22, the fluid motor I! alone may support very nearly all of the weight of the empty elevator, the area of the two fluid motors together being suilicient to raise the the use of the pump 30. To raise the elevator the valve 42 is shifted to the position of Figure 2 so that both fluid motors are connected to the accumulator. Fluid thus flows from the accumulator through conduit 20 to the first fluid motor and through conduit 44, ports 46 and 50, and conduits 52 and 26 to the second fluid motor. The elevator is thus caused to rise independently of any power supplied by the pump 30.

If it is desired to lower the elevator without using the pump 30, the valve 42 is moved to the position of Figure 3 wherein the port is connected to the port 54. Fluid from the second fluid motor is' thus permitted to discharge through the conduits 26 and 52, ports 50 and 54, and conduit 56 to the overflow tank 58.

It will be apparent that by the use of two fluid motors the volumetric capacity required at the pump is considerably reduced since the volume displaced by the second fluid motor is all that must be passed through the pump. Likewise, by choosing the areas of the two motors as above described the accumulator is made to perform the function of a counterweight with the added advantage fo being able to selectively vary its effect for emergency operation. During normal operation the pump operates to drive the elevator down, so to speak, and transfers the energy input of the electric motor to the accumulator. On raising, the pump operates as a fluid metering. device to control the ascent on energy stored in the accumulator.

Obviously the load to be raised may be positioned either on the platform ill or, by using platform I0 as the support for weight 24, the platform 25 may carry the load to be raised with or without shifting the cable 96 to platform 25.

form, it is to be understood thatother form's might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a hydraulic elevator systemthe combination of a first fluid motor and a second fluid motor for operating the elevator, an accumulator having means for maintaining a nearly constant fully loaded elevator under the pressure normally existing in the accumulator 22.

If the lowering push button II2 be closed, the pilot motor I04 is operated in the reverse direction moving 'the pump into stroke in the opposite direction so as to withdraw fluid from the second fluid motor 2| through the conduit 25 and deliver fluid to the accumulator through the conduit 28, ports 40 and 45, and the conduits .44 and 20. The operation of the follow-up mechanism on lowering is identical to that described previously except that the motions take place in the opposite direction.

If for any reason it should be impossible to opfluid pressure therein, said first fluid motor being effective to sustain a major portion only of the weight of the empty elevator at the pressure maintained by said accumulator, said two motors together being efiective to raise the loaded elevator at said pressure, conduit means connecting the first fluid motor to the accumulator at all times, and a reversible variable displacement pump connected between the accumulator and the second fluid motor.

2. In a hydraulic elevator system the combination of a flrst fluid motor and a second fluid motor for operating the elevator, an accumulator having means for maintaining a nearly constant fluid pressure therein, said first fluid motor erate the pump 30, such as failure of electric being effective to sustain a major portion only of the weight of the empty elevator at the presi bump connected between the accumulatorand the second fluid motor, and means for selectively bypassing fluid from the accumulator to the second fluid motor around the pump whereby the elevator may be raised through at least one flight on energy stored in the accumulator.

'3. In ahydraulic elevator system the combination of a first fluid motor and a second fluid motor for operating the elevator, an accumulator having means for maintaining a nearly constant fluid pressure therein, said first fluid motor being effective to sustain a major portion only of the weight of the empty elevator at the pressure maintained by said accumulator, said two motors together being effective to raise the loaded elevator at said pressure, conduit means conincluding a pump operable to remove fluid from the second motor and store energy in the accunecting the first fluid motor to the accumulator at all times, a reversible variable displacement pump connected between the accumulator and the second fluid motor, and means for selectively exhausting fluid from the second fluid motor whereby the elevator may be lowered through at least one cycle independently of the pump.

4. In a hydraulic elevator system the combination of a first fluid motor and a second fluid motor for operating the elevator, an accumulator having means for maintaining a nearly constant fluid pressure therein, said first fluid motor befluidbetween another of said 'eflective areas of V ing efl'ectiveto sustain a major portion only of.-

the weight of the empty elevator at the pressure maintained by said accumulator, said two motors together being eflective to raise the loaded elevator at said pressure, conduit means connecting the first fluid motor to the accumulator at all times, a reversible variable displacement pump connected betweenthe accumulator and the second fluid motor, and a three-position valve for selectively connecting the second fluid motor either to the pump for power operation in either direction or to the accumulator for raising the elevator on energy stored in the accumulator or to exhaust for lowering the elevator by gravity;

5. In a hydraulic elevator system the combination of a first fluid motor and a second fluid motor for operating the elevator, an accumulator having means for maintaining a nearly constant ing eflective to sustain a major portion only of the weight of the empty elevator at the pressure maintained by said accumulator, said two motors together being effective to raise the loaded elevator at said'pressure, conduit means connecting the first fluid motor to the accumulator at all times, and means for controlling the transfer of fluid between the accumulator and the second fluid motor to raise and ower the elevator including a pump operable to remove fluid from the second motor and store energy in the accumulator and allow the elevator to descend by gravity. 6 In a hydraulic elevator system the combination of a first fluid motor and a second fluid mulator and allow the elevator to descend by gravity, and means for controlling said pump to cause the pump to act as a fluid metering device for raising the elevator.

7. In a'hydra'ulic elevator system the combination of fluid motor means for operating the elevator, accumulator means for storing fluid under pressure, one of said means being constructed to selectively provide a plurality of eflective areas exposed to pressure of the operating fluid, said means being proportioned one to the other so that when one of said areas is eflective the accumulator will sustain only a portion of the weight of the unloaded elevator, and when another area is efiective the accumulator will exert sumcient force to raise the loaded elevator, conduit means permanently connecting one of said eflective areas of said one means to the other means, and means controlling the transfer of said one means and the other means to raise and lower the elevator, including a pump to remove fluid from the motor means and store energy in the accumulator and allow the elevator to descend by gravity.

8. In a hydraulic elevator system the combination of fluid motor means for operating the elevator, accumulator means for storing fluid under a pressure, one of said means being constructed to selectively provide a plurality of effective areas exposed to pressure of the operating fluid, said means being proportioned one to the other so that when one of said areas is effective the accumulator will sustain only a portion of the weight of the unloaded elevator, and when another area is eflective the accumulator will exert suificient force to raise the-loaded elevator, conduit means permanently connecting one of said efiective areas of said one means to the other means, means controlling thetransfer of fluid fluid pressure therein, said first fluid motor benecting the first fluid motor to the accumulator at all times, means for controlling the transfer of fluid between the accumulator and the secbetween another of said effective areas of said one means and the other means to raise and lower the elevator, including a pump to remove fluid from the motor means and store energy inv the accumulator and allow the elevator to descend by gravity, and means for causing the pump to act as a fluid metering device for raising .the elevator;

9. In -'a hydraulic elevator system the combination of fluid motor means for operating the elevator, accumulator means for storing fluid under pressure, one of said means being constructed to selectively provide a plurality of effective areas exposed to pressure of the operating fluid, said means being proportioned one to the other so that when one of said areas is eflective the'accumulator will sustain only a portion of the weight of the unloaded elevator, and when another area is efiecti've the accumulator will exert 10. In a hydraulic elevatorsystem the combination of fluid motor means for operating theelevator, accumulator means for storing fluid i said efiective areas of said one means to the other means, means including a pump controlling the transfer of fluid between another of said effective areas of said one means and the other means to raise and lower the elevator, and means for selectively controlling the exhausting of fluid from one of said means to cause operation of said elevator in one direction through one cycle independently of said pump.

11. In a hydraulic elevator system the combination of fluid motor means foroperating the elevator, accumulator means for storing fluid under pressure, one of said means being constructed to selectively provide a plurality of effective areas exposed to pressure of the operating fluid, said means being proportioned one to the other so that when one of said areas is effective the accumulator will sustain only a portion of the weight of the unloaded elevator, and when another area is effective the accumulator will exert suificient force to raise the loaded elevator, conduit means permanently connecting'one' of said efiective areas of said one means to the other means, means including a pump controlling the transfer of fluid between another of said effective areas of said one means and the other means to raise and lower the elevator, and means forselectively controlling the bypassing of fluid between said means to cause operation of said elevator in one direction through one cycle independently of said pump, and for selectively controlling the exhausting of fluid from one of said means to cause operation of said elevator in the opposite direction through one-cycle independently of said pump.

EDWIN L. ROSE. 

